We evaluated the combined effect of admission systolic blood pressure (SBP) and antecedent hypertension on short-term outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Data were derived from a multicenter survey of 7303 consecutive patients with STEMI. Patients were divided into 4 groups according to different blood pressure status: high SBP without hypertension, high SBP with hypertension, low SBP without hypertension, and low SBP with hypertension. The primary endpoints were 7 and 30-day all-cause mortality. The prevalence of hypertension was 40.7%, and the best cutoff of admission SBP for predicting 30-day mortality was 108 mmHg by receiver-operating characteristic curve. Patients with hypertension were older, more often female, also had longer onset-to-admission time, more comorbidities, and higher Killip class. Patients with both low SBP (≤108 mmHg) and hypertension group had significantly higher 7 and 30-day mortality than those in other groups (all P < 0.001). After multivariate adjustment, low SBP with hypertension group was still an independent risk factor for predicting 7-day mortality (hazard ratios [HR] 1.86, 95% confidence interval [CI] 1.41-2.46; P < 0.001) and 30-day mortality (HR 1.88, 95% CI 1.46-2.43; P < 0.001). In patients with SBP > 108 mmHg, a history of hypertension could increase the risk of 30-day mortality by 27% (HR 1.00 vs 1.27, P = 0.012), while in patients with SBP ≤ 108 mmHg, this increased risk reached to 37% (HR 1.51 vs 1.88, P < 0.001). In conclusion, low admission SBP was the relatively dominant contributor for predicting 7 and 30-day all-cause mortality, and a concurrent antecedent hypertension increased the corresponding risk of mortality.